Package structure including a package lid having a patterned bottom surface and methods of forming the same

Abstract

A package structure includes a package substrate, a package module on the package substrate, a thermal interface material (TIM) layer on the package module, and a package lid on the TIM layer. The package lid includes a package lid foot portion attached to the package substrate, and a package lid plate portion on the package lid foot portion and including a patterned bottom surface having a plurality of recessed portions, wherein at least a portion of the TIM layer is located in the plurality of recessed portions.

What is claimed is: 
     
         1 . A package structure, comprising:
 a package substrate;   a package module on the package substrate;   a thermal interface material (TIM) layer on the package module; and   a package lid on the TIM layer, comprising:
 a package lid foot portion attached to the package substrate; and 
 a package lid plate portion including a patterned bottom surface having a plurality of recessed portions, wherein at least a portion of the TIM layer is located in the plurality of recessed portions. 
   
     
     
         2 . The package structure of  claim 1 , wherein the TIM layer comprises one of a polymer-based phase change material or a low-melting-temperature metal. 
     
     
         3 . The package structure of  claim 1 , wherein the TIM layer has a first thickness at the plurality of recessed portions and a second thickness less than the first thickness outside the plurality of recessed portions, and the first thickness is in a range from 50 μm to 1000 μm. 
     
     
         4 . The package structure of  claim 3 , wherein a ratio of a depth of the plurality of recessed portions to the first thickness of the TIM layer is in a range from 0.2 to 0.8. 
     
     
         5 . The package structure of  claim 1 , wherein the plurality of recessed portions are substantially filled by the TIM layer. 
     
     
         6 . The package structure of  claim 1 , wherein a width of the plurality of recessed portions is in a range from 100 μm to 1000 μm. 
     
     
         7 . The package structure of  claim 1 , wherein the plurality of recessed portions are arranged in staggered array having a plurality of columns, wherein the plurality of recessed portions within a column of the plurality of columns are separated by a distance in a range from 100 μm to 1000 μm. 
     
     
         8 . The package structure of  claim 7 , wherein the column of the plurality of columns is separated from an adjacent column of the plurality of columns by a distance in a range from 100 μm to 1000 μm. 
     
     
         9 . The package structure of  claim 1 , wherein a concentration of the plurality of recessed portions varies over the patterned bottom surface. 
     
     
         10 . The package structure of  claim 1 , wherein the plurality of recessed portions comprises one of a hexagon shape, a round shape, and oval shape, a capsule shape, a rounded rectangular shape, a square shape, a rectangular shape, a triangular shape, a trapezoid shape and a diamond shape. 
     
     
         11 . The package structure of  claim 1 , further comprising:
 a surface mount device (SMD) attached to the package substrate between the package lid foot portion and the package module.   
     
     
         12 . The package structure of  claim 11 , wherein the SMD comprises one of a rectifier, capacitor or voltage regulator. 
     
     
         13 . The package structure of  claim 1 , wherein an outermost recessed portion of the plurality of recessed portions is located over the package module. 
     
     
         14 . The package structure of  claim 13 , wherein a distance between an outer sidewall of the package module and the outermost recessed portion is in a range from 0.5 mm to 1.0 mm. 
     
     
         15 . A method of forming a package structure, comprising:
 forming a package lid comprising a package lid foot portion and a package lid plate portion on the package lid foot portion, wherein the package lid plate portion comprises a patterned bottom surface having a plurality of recessed portions;   attaching a package module to a package substrate;   placing a thermal interface material (TIM) layer on the package module; and   attaching the package lid to the package substrate such that the package lid plate portion is on the package module and at least a portion of the TIM layer is disposed in the plurality of recessed portions.   
     
     
         16 . The method of  claim 15 , wherein the attaching of the package lid to the package substrate comprises pressing the patterned bottom surface of the package lid plate portion onto the TIM layer such that the plurality of recessed portions are substantially filled with the TIM layer. 
     
     
         17 . The method of  claim 15 , wherein the forming of the package lid comprises forming a width of the plurality of recessed portions to be in a range from 100 μm to 1000 μm. 
     
     
         18 . The method of  claim 15 , wherein the forming of the package lid comprises forming the plurality of recessed portions to be arranged in staggered array having a plurality of columns, wherein the plurality of recessed portions within a column of the plurality of columns are separated by a distance in a range from 100 μm to 1000 μm. 
     
     
         19 . The method of  claim 18 , wherein the forming of the package lid comprises forming the column of the plurality of columns to be separated from an adjacent column of the plurality of columns by a distance in a range from 100 μm to 1000 μm. 
     
     
         20 . A package structure, comprising:
 a package substrate;   a package module on the package substrate;   a package lid over the package module, comprising:
 a plate portion having a bottom surface including recessed structures; and 
 a foot portion connected to the plate portion and attached to the package substrate; and 
   a thermal interface material (TIM) layer between the package module and the bottom surface of the plate portion.